The young action/tower defense genre received a great, but overlooked, addition in 2011 with Coffee Stain Studios’ Sanctum. This summer, the developer looks to improve on their formula with Sanctum 2. I managed to get my hands on a preview build of the game. Even as an unfinished product, Sanctum 2 blew me away.

Sanctum 2 creates an experience that requires both twitch reflexes and a knack for battle tactics to win. The combination works exceptionally well, not allowing the player to rely solely on either tower defense or first-person shooting to win. I know this from firsthand experience.

I am much more adept at shooting games than tower defense games. During the first few levels, I didn’t put a lot of effort into building a good defense. I was destroyed. Only when I learned how to use tower defense to thin out the horde of enemies did I survive. It goes the other way too. Not even the most well-crafted tower setup will win the game; the bases will fall without extra firepower from the player.

To help you with the wave of enemies you’ll face at the start of each level, the game provides you with new tower bases and some points to spend on turrets. These items can be picked up at the “core” – though if I had my way, they’d automatically appear in the inventory. Reaching the core requires an annoying trek that takes precious seconds out of the planning needed to survive the next round.

Despite the inconvenience of having to retrieve items, the game gives you time to set up bases and outfit them with different kinds of turrets. I recommend taking the time to prepare an adequate defense. A variety of enemies – many of which are equipped with weapons designed to demolish your bases – await you during each wave. These enemies include suicide bombers, Imperial Walker style tanks, and flying insects. The game will occasionally even throw a boss at you. If defense isn’t taken seriously, not even the best FPS player in the world will be able to win.

Every time you die it takes a precious ten seconds to respawn. Ten seconds is all you need in order to watch a carefully constructed base crumble before a determined enemy wave. Unfortunately, death perpetually feels close at hand because it’s hard to tell when you’re going to finally bite the dust. The screen darkens as you lose health – a frustrating and unreliable form of measurement. I found myself wishing for a more obvious health bar.

Sanctum 2 changes a lot of features from the first game. These changes include fewer waves (ten instead of thirty), the ability for enemies to attack you directly, and the ability to jump over your own turret bases. There are also more maps: sixteen at launch -- compared with three in the original. The streamlined feel of Sanctum 2 makes the original game look like a test run.

Sanctum 2 also includes more of everything – more weapons, more turrets, and more perks. Some of my favorite unlockables are a rifle that fires explosive charges and a turret that deals massive damage to the enemies. Coffee Stain Studios also includes the ability to pick a different character before each level. Each character represents a different FPS stereotype based on preferred weapon types: assault rifle, shotgun, sniper rifle, and grenade launcher. The variety added by having four ways to play each mission benefits the game despite the characters not being very innovative.

A surprising amount of hours are contained within this DLC game. Each of Sanctum’s 16 maps will take you half an hour to an hour to complete. This time can be extended if restarts are included, and Sanctum 2 holds enough surprises to make sure of that. It took me awhile to get through a level without dying a frustrating number of times. As soon as I felt comfortable enough with the gameplay to not die repeatedly, the game decided to torment me by introducing flying enemies.

Coffee Stain Studios created an easy to use control scheme to help you cope with the surprises the game has in store. The well implemented controls make it easy to maneuver in FPS mode and to place objects in tower defense mode. The developer doesn’t just assume that the standard control scheme will be the best for you, though. Those who dislike the default controls can change them.

Sanctum 2 effectively combines two genres. As a result, it's more thoughtful than your typical FPS and more exhilarating than your typical tower defense game. I had more fun with this incomplete DLC build than I've had with many finished, fully priced games. Sanctum 2 just might be a must-buy.